Lens, lens molding mold, and manufacturing device for lens molding mold

Abstract

This invention provides a lens with excellent positioning accuracy and high productivity. The lens is a glass compression molding product and has: an optical functional part (11) having a first optical surface (12) and a second optical surface (13); a frustum-shaped position reference surface (16) disposed at the edge (14), the radius of curvature of which increases as it moves from the first optical surface side to the second optical surface side; and a volume absorption part (19) disposed at the edge, located at a position more inside the orthogonal direction of the optical axis than the outer edge (Q3) of the position reference surface. The angle θ of the position reference surface relative to the plane (P) perpendicular to the optical axis, the distance w from the outer edge (Q1) of the first optical surface to the inner edge (Q2) of the position reference surface in the direction perpendicular to the optical axis, and the distance d from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction parallel to the optical axis, satisfy conditions (1) and (2) when 0° < θ < 45°: (1) d <w(2)d<w·tanθ。

Description

[0001] This application is a divisional application of utility model patent application number 202323224227.8, the original application being filed on November 28, 2023, with the utility model title "Lens, Lens Forming Mold, and Manufacturing Apparatus for Lens Forming Mold". Technical Field

[0002] This utility model relates to lenses, lens forming molds, and manufacturing apparatus for lens forming molds. Background Technology

[0003] A typical lens has an edge portion around the periphery of its optical functional part, which has an optical surface (lens surface). This edge portion is mounted on a holding member such as a lens barrel or lens frame. The position of the lens relative to the optical system is managed by its position along the optical axis, its position in a direction perpendicular to the optical axis (hereinafter referred to as the orthogonal direction of the optical axis), and the tilt of the optical system relative to the optical axis. For example, the edge portion has a plane perpendicular to the optical axis on at least one side before and after the optical axis, and the lens position along the optical axis is positioned with reference to this plane. Furthermore, the edge portion has a cylindrical outer peripheral surface surrounding the optical axis, and the lens position in the orthogonal direction of the optical axis is positioned with reference to this outer peripheral surface.

[0004] In recent years, the miniaturization of camera units on portable electronic devices such as smartphones has become significant, requiring the lenses that make up the camera units to be small and lightweight.

[0005] In addition, in order to efficiently manufacture glass lenses, there are known methods for manufacturing glass molded lenses by pressing and molding a glass preform as a base material using a molding die (for example, Patent Documents 1-4).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2005-325022;

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-147715;

[0010] Patent document 3: Japanese Patent Application Publication No. 2017-065957;

[0011] Patent document 4: Japanese Patent Application Publication No. 2022-107530.

[0012] Problems to be solved by utility models

[0013] Regarding the miniaturization and weight reduction of lenses, it is desirable to thin the edge. However, due to the following reasons, the freedom of freedom in the shape and structure of the edge of a glass lens is limited, making it difficult to thin the edge.

[0014] In glass molded lenses, a volume-absorbing section is provided at the edge to absorb various errors related to the capacity or supply position of the glass preform, the volume of the internal space of the molding die (mold space), etc. Since the volume-absorbing section is a part that allows for shape deviations, the area of ​​the volume-absorbing section in the edge cannot be used for positioning the lens relative to the holding member. If the area for lens positioning cannot be sufficiently ensured at the edge, the positional accuracy and stability of the lens will deteriorate. Therefore, in addition to having dimensions sufficient to achieve high-precision positioning, the edge also needs to accommodate the dimensions of the volume-absorbing section for absorbing errors during molding, thus limiting the miniaturization of the edge.

[0015] Furthermore, in the manufacturing of conventional glass molded lenses, due to the constraints of the molding die structure, it is difficult to form the edge with high precision while making the outer peripheral surface of the edge elongated in the optical axis direction.

[0016] Furthermore, considering the productivity of molding dies used for molding glass lenses, in conventional molding dies for glass lenses, the orientations of the surfaces forming the optical surface and the outer peripheral surface forming the edge are quite different, making it difficult to continuously form them using the same machining tools (e.g., grinding wheels). This necessitates changing the machining tools during mold manufacturing, leading to potential deviations in the accuracy of different parts of the molding die and hindering efficient machining. Utility Model Content

[0017] This invention is based on an understanding of the above-mentioned problems, and its purpose is to provide a lens with excellent positioning accuracy and high productivity. Furthermore, this invention aims to provide a lens forming mold and a lens forming mold manufacturing apparatus capable of efficiently producing such lenses.

[0018] Solution for solving the problem

[0019] This utility model is a lens, which is a pressed glass product, characterized by having: an optical functional part having a convex surface, i.e., a first optical surface, facing the optical axis, and a second optical surface facing the optical axis; a frustum-shaped position reference surface disposed on the outer edge of the optical functional part, the radius of curvature of which increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction; and a volume absorption part disposed on the edge, located on the inner side of the orthogonal direction of the optical axis, which allows for shape errors associated with pressing and molding. The angle θ of the position reference surface relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction perpendicular to the optical axis, and the distance d from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction parallel to the optical axis, satisfy the following conditions (1) and (2) when 0° < θ < 45°:

[0020] (1)d<w

[0021] (2)d<w·tanθ.

[0022] Furthermore, this utility model is a lens, which is a glass compression molding product, characterized in that it has: an optical functional part having a convex surface, namely a first optical surface, facing one side in the optical axis direction, and a second optical surface facing the other side in the optical axis direction; a frustum-shaped position reference surface, which is disposed on the outer edge of the optical functional part, the radius of curvature of which increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction; and a volume absorption part, which is disposed on the edge, located on the inner side of the optical axis orthogonal direction more than the outer edge of the position reference surface, allowing for shape errors associated with compression molding, wherein the angle θ of the position reference surface relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference surface in the direction perpendicular to the optical axis, the distance d from the outer edge of the first optical surface to the inner edge of the position reference surface parallel to the optical axis, and the paraxial radius of curvature R1 of the first optical surface, when θ < 90°, satisfy the following conditions (3) and (4).

[0023] (3)w·tan(θ-45°)<d<w<w·tanθ

[0024] (4) d>1.1R1·sin(θ-45°)

[0025] Preferably, the position reference surface is disposed on the outer periphery of the edge portion, and the edge portion has a curved surface with a radius of curvature that increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction, or has the same radius of curvature, on the inner side of the edge portion that is closer to the optical axis direction than the position reference surface. The volume absorption portion is disposed at the end of the flange portion that has the position reference surface as the outer periphery surface and the curved surface as the inner periphery surface.

[0026] The curved surface is the inner conical surface of a frustum shape, whose radius of curvature increases as it moves along the optical axis from the first optical surface side to the second optical surface side. In this case, preferably, the position reference plane has a larger angle of inclination relative to the plane perpendicular to the optical axis compared to the inner conical surface.

[0027] Alternatively, the surface can be a surface whose radius of curvature increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction, and has a concave shape within a cross section containing the optical axis.

[0028] Preferably, there is an intermediate surface between the first optical surface and the position reference surface, and in a cross section including the optical axis, the intermediate surface is located in the region enclosed by the line segment connecting the outer edge of the first optical surface and the inner edge of the position reference surface, the straight line extending from the outer edge of the first optical surface in the orthogonal direction of the optical axis, and the straight line extending the position reference surface.

[0029] Furthermore, this utility model is a lens forming mold for forming the aforementioned lens, characterized in that it comprises: a mold component having an optical surface forming surface having a shape corresponding to the first optical surface, and a position reference surface forming surface having a shape corresponding to the position reference surface.

[0030] Furthermore, this utility model is a manufacturing apparatus for manufacturing the above-mentioned lens forming mold, characterized in that it has: a grinding wheel, which is cylindrical, and forms the optical surface forming surface and the position reference surface forming surface of the mold component by rotating about a central axis, wherein the paraxial radius of curvature R1 of the first optical surface of the lens and the diameter φg of the end face of the grinding wheel satisfy the following condition (5):

[0031] (5)

[0032] Utility Model Effect

[0033] According to the lens of this invention, by satisfying various conditions, excellent positioning accuracy using a position reference plane can be achieved, and excellent productivity can be obtained. Furthermore, the lens forming mold and the lens forming mold manufacturing apparatus of this invention enable efficient production of the aforementioned lens. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view of the lens in this embodiment.

[0035] Figure 2 This is a magnified cross-sectional view of a portion of the lens.

[0036] Figure 3 This is a cross-sectional view of the molding die used to press and form the lens according to this embodiment.

[0037] Figure 4 This is a cross-sectional view showing the grinding wheel used to machine the lower die of a molding die.

[0038] Figure 5 This is a cross-sectional view showing the process of machining the optical surface of the lower mold using a grinding wheel.

[0039] Figure 6 This diagram illustrates the machining conditions for processing a lower mold using a grinding wheel.

[0040] Figure 7 This diagram illustrates the machining conditions for processing a lower mold using a grinding wheel.

[0041] Figure 8 This is a cross-sectional view showing a modified example of the flange portion of the lens.

[0042] Figure 9 This is a cross-sectional view showing a modified example of the flange portion of the lens.

[0043] Figure 10 This is a cross-sectional view showing a modified example of the flange portion of the lens. Detailed Implementation

[0044] Figure 1 The lens 10 shown is a glass molded lens formed by pressing glass material (glass preform) through the molding die 30 described later. Figure 2 This is a magnified view of a portion of lens 10. The direction along the optical axis A of lens 10 is defined as the optical axis direction, and the direction perpendicular to optical axis A is defined as the orthogonal direction of the optical axis. The orthogonal direction of the optical axis can also be referred to as the radial direction of lens 10.

[0045] Figure 1 and Figure 2 The shape of the lens 10 is shown in a cross-section containing the optical axis A. The cross-section containing the optical axis A refers to a cross-section parallel to and containing the optical axis A. The lens 10 has rotational symmetry, exhibiting a continuous shape in the circumferential direction centered on the optical axis A. At any position in the circumferential direction of the lens 10, the shape of the lens 10 within the cross-section containing the optical axis A is approximately the same (except for deviations in the shape used for error absorption in the volume absorption section 19, which will be described later).

[0046] Lens 10 has an optical functional section 11. A first optical surface 12 and a second optical surface 13 are formed in the optical functional section 11. The first optical surface 12 is a convex surface facing the optical axis direction, i.e., the first direction A1. The second optical surface 13 is a convex surface facing the other side of the optical axis direction, i.e., the second direction A2. In this embodiment, both the first optical surface 12 and the second optical surface 13 of lens 10 are aspherical lenses. The outer edge (peripheral portion in the direction orthogonal to the optical axis) of the first optical surface 12 is defined as the outer edge Q1 of the optical surface.

[0047] The lens 10 has an edge portion 14 on the outer side of the optical functional section 11. The edge portion 14 has a base portion 14a that surrounds the optical functional section 11 and a flange portion 14b located on the outer side of the base portion 14a. The base portion 14a is formed into an annular shape extending from the optical functional section 11 in a direction generally orthogonal to the optical axis. The flange portion 14b protrudes relative to the base portion 14a in a second direction A2 and is a tapered annular portion with a predetermined inclination relative to the optical axis direction.

[0048] Edge portion 14 has a middle surface 15 located outside the first optical surface 12 and a position reference surface 16 located outside the middle surface 15, serving as an outer surface facing the first direction A1. Furthermore, edge portion 14 has a flat surface 17 located outside the second optical surface 13 and an inner conical surface 18 located outside the flat surface 17, serving as an outer surface facing the second direction A2. The middle surface 15 and the flat surface 17 constitute the outer surface of base portion 14a. Additionally, the position reference surface 16 constitutes the outer peripheral surface of flange portion 14b, and the inner conical surface 18 constitutes the inner peripheral surface of flange portion 14b.

[0049] The position reference surface 16 is located on the outer periphery of the edge portion 14 and is a frustum-shaped (side surface of the frustum) centered on the optical axis A. The diameter of the position reference surface 16 increases as it advances along the optical axis in the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13). That is, the position reference surface 16 is a curved surface whose radius of curvature (the radius of curvature of the circle passing through the position reference surface 16 centered on the optical axis A) increases as it advances along the optical axis in the second direction A2. In the position reference surface 16, the portion intersecting with the intermediate surface 15 is designated as the inner edge Q2 of the position reference surface, and the outer edge portion (the peripheral portion in the orthogonal direction of the optical axis) opposite to the inner edge Q2 of the position reference surface is designated as the outer edge Q3 of the position reference surface. The outer edge Q3 of the position reference surface is located at the outermost edge in the orthogonal direction of the optical axis of the lens 10.

[0050] The intermediate surface 15 is the surface connecting the outer edge Q1 of the first optical surface 12 to the inner edge Q2 of the position reference surface 16. In this embodiment, the intermediate surface 15 is composed of an annular flat surface 15a extending from the outer edge Q1 of the optical surface in a direction orthogonal to the optical axis, and a conical surface 15b extending from the flat surface 15a to the inner edge Q2 of the position reference surface. The conical surface 15b is a truncated cone shape (the side of the truncated cone) centered on the optical axis A, and its diameter increases as it moves towards the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13). That is, the conical surface 15b is a surface whose radius of curvature (the radius of curvature of the circle passing through the conical surface 15b centered on the optical axis A) increases as it moves towards the second direction A2 in the optical axis direction. The tilt angle of the conical surface 15b relative to the optical axis A is greater than the tilt angle of the position reference surface 16 relative to the optical axis A. Conditions related to the shape of the intermediate surface 15 will be described later.

[0051] The flat surface 17 is a plane perpendicular to the optical axis A. The inner conical surface 18 is a frustum-shaped (the side of a frustum) centered on the optical axis A, and its diameter increases as it moves along the optical axis towards the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13). That is, the inner conical surface 18 is a surface whose radius of curvature (the radius of curvature of the circle passing through the inner conical surface 18 centered on the optical axis A) increases as it moves along the optical axis towards the second direction A2. The inner conical surface 18 is approximately parallel to the position reference plane 16.

[0052] When assembling the lens 10 into a retaining member (not shown) such as a lens barrel or lens frame, the position reference surface 16 is brought into contact with a positioning portion (not shown) of the retaining member. Since the position reference surface 16 is inclined relative to both the optical axis direction and the direction orthogonal to the optical axis, the position of the lens 10 in both the optical axis direction and the direction orthogonal to the optical axis can be determined when the position reference surface 16 is brought into contact with the positioning portion of the retaining member. Furthermore, the orientation of the optical axis A relative to the retaining member (the inclination of the lens 10) can also be determined when the position reference surface 16 is brought into contact with the positioning portion of the retaining member. Because the position reference surface 16 is located on the outer periphery of the edge portion 14 and is positioned away from the optical axis A, the position and orientation of the lens 10 can be determined with high precision.

[0053] The flange 14 also has a volume absorption portion 19 at the end of the flange 14b, between the position reference surface 16 and the inner conical surface 18. The volume absorption portion 19 is used to absorb errors when the lens 10 is formed by the forming mold 30, which will be described later.

[0054] In the rim portion 14, a positioning reference surface 16 for the lens 10, which has a positioning function, is provided on the outer peripheral surface of the tapered flange portion 14b, and a volume absorption portion 19, which has an error absorption function during molding, is provided at the end of the tapered flange portion 14b, so that the size of the positioning reference surface 16 is not limited by the volume absorption portion 19. As a result, the positioning accuracy of the lens 10 using the positioning reference surface 16 can be improved. In addition, the rim portion 14 can be miniaturized and thinned.

[0055] As a lens different from the lens 10 of this embodiment, lenses of the following type are widely used: the edge has an orthogonal plane extending in the orthogonal direction of the optical axis, and a cylindrical outer peripheral surface centered on the optical axis A. The optical axis direction is positioned by the orthogonal plane of the edge, and the orthogonal direction of the optical axis is positioned by the outer peripheral surface of the edge. In this type of lens, a volume absorption portion is usually provided as an angle R portion at the junction of the orthogonal plane of the optical axis and the outer peripheral surface in the edge. Since the shape of the volume absorption portion varies depending on the degree of error, it cannot be used for lens positioning. That is, the effective area of ​​the orthogonal plane of the optical axis and the outer peripheral surface used for lens positioning is reduced by the amount of volume absorption portion. Therefore, in order to obtain the desired positioning performance, it is necessary to estimate the amount of reduction in effective area caused by the volume absorption portion and set the size of the edge in the optical axis direction and the orthogonal direction of the optical axis to be large.

[0056] In contrast, in the lens 10 of this embodiment, the volume absorption portion 19 is provided at the end of the flange portion 14b in the edge portion 14, and not on the extension line of the positioning reference surface 16 (the outer peripheral surface of the flange portion 14b). Moreover, the volume absorption portion 19 is located in the orthogonal direction of the optical axis, which is more inward than the outer edge Q3 of the positioning reference surface 16, and in the optical axis direction, it is located on the back side of the positioning reference surface 16.

[0057] According to this structure, the effective area of ​​the position reference surface 16 is not reduced by the volume absorption portion 19, and the edge portion 14 is not enlarged in the direction orthogonal to the optical axis in order to provide the volume absorption portion 19. Furthermore, by concentrating the volume absorption portion 19 at the end of the flange portion 14b, the variation in the degree of expansion of the flange portion 14b towards the end side can be used to absorb errors during molding. Therefore, it is not necessary to reserve a margin for error absorption in the thickness direction of the edge portion 14 (the interval between the intermediate surface 15 and the flat surface 17, and the interval between the position reference surface 16 and the inner conical surface 18), and the edge portion 14 can be made thinner. As a result, the positioning performance using the position reference surface 16 is not compromised, and the edge portion 14 with the volume absorption portion 19 can be compactly constructed.

[0058] The base 14a of the edge 14 has a flat surface 15a and a flat surface 17 perpendicular to the optical axis A on both sides in the optical axis direction. Figure 3When the lens 10 is formed by the forming mold 30, the flat surface 15a is formed by transferring the shape of the flat surface 36a, a portion of the pressing surface 34 of the lower mold 32 (described later), and the flat surface 17 is formed by transferring the shape of the flat surface 40, a portion of the pressing surface 38 of the upper mold 33 (described later). If both the flat surface 15a and the flat surface 17 are planes perpendicular to the optical axis A, the tilt of the optical axis of the first optical surface 12 located inside the flat surface 15a and the second optical surface 13 located inside the flat surface 17 can be evaluated by examining the parallelism of the flat surface 15a and the flat surface 17.

[0059] Furthermore, if the flat surface 15a is a plane perpendicular to the optical axis A, then on the pressing surface 34 of the lower mold 32 described later, the optical surface forming surface 35 that forms the first optical surface 12 can be measured (refer to) with reference to the flat surface 36a that forms the flat surface 15a. Figure 3 The depth of the optical surface forming surface 35 can be precisely managed within the lower mold 32. Similarly, if the flat surface 17 is a plane perpendicular to the optical axis A, the optical surface forming surface 39 forming the second optical surface 13 can be measured on the pressing surface 38 of the upper mold 33, using the flat surface 40 forming the flat surface 17 as a reference (see reference). Figure 3 The depth of the optical surface forming surface 39 can be managed with high precision in the upper mold 33.

[0060] Therefore, by having a flat surface 15a and a flat surface 17 perpendicular to the optical axis A in the base 14a of the edge 14, the optical accuracy of the first optical surface 12 and the second optical surface 13 of the lens 10 is improved.

[0061] The lens 10, as an optical component, has the advantages described above. Furthermore, by making the position reference surface 16 of the lens 10 a conical surface inclined relative to the optical axis A, the angular difference between the first optical surface 12 and the position reference surface 16 is reduced. Therefore, in the mold component (lower mold 32 described later) used for pressing and molding the lens 10, it is easy to manufacture the portion forming the first optical surface 12 and the portion forming the position reference surface 16 using a common processing tool. Specifically, in the lens 10 with the above structure, the productivity of the lens 10 can be improved by satisfying the following conditions.

[0062] like Figure 2As shown, the angle between the position reference plane 16 and the plane P perpendicular to the optical axis A is defined as θ. Since the position reference plane 16 is a conical surface whose radius of curvature increases as it moves towards the second direction A2 along the optical axis, 0° < θ < 90°. The distance from the outer edge Q1 of the optical surface to the inner edge Q2 of the position reference plane in the direction perpendicular to the optical axis A is defined as w. The distance from the outer edge Q1 of the optical surface to the inner edge Q2 of the position reference plane in the direction parallel to the optical axis A is defined as d. The paraxial radius of curvature of the first optical surface 12 is defined as R1.

[0063] Lens 10 satisfies the following conditions (1) and (2) when the axis is 0° < θ < 45°.

[0064] (1)d<w

[0065] (2)d<w·tanθ

[0066] Lens 10 satisfies the following conditions (3) and (4) when 45°≤θ<90°.

[0067] (3)w·tan(θ-45°)<d<w<w·tanθ

[0068] (4) d>1.1R1·sin(θ-45°)

[0069] like Figure 2 As shown, preferably within a cross-section containing the optical axis A, the intermediate surface 15 of the lens 10 is contained within a triangular region enclosed by the line segment La connecting the outer edge Q1 of the optical surface and the inner edge Q2 of the position reference surface, the vertical line Lb perpendicular to the optical axis A, and the extension line Lc extending the position reference surface 16. The flat surface 15a is the surface along the vertical line Lb, the conical surface 15b is the surface located between the line segment La and the extension line Lc, and the intermediate surface 15 satisfies this condition.

[0070] Furthermore, the intermediate surface between the first optical surface 12 and the position reference surface 16 is not limited to the shape of the intermediate surface 15 shown in the figure. For example, it is also possible to configure the intermediate surface in the above-mentioned region as a continuous surface with a shape close to the inclination of the line segment La, instead of dividing it into a flat surface 15a and a conical surface 15b as the intermediate surface 15 is.

[0071] The basis for the above-mentioned conditions for lens 10, and the relationship between the forming mold 30 for forming lens 10 and the manufacturing apparatus for manufacturing forming mold 30, will be explained in detail.

[0072] Figure 3The molding die 30 is shown. The molding die 30 consists of a shell mold 31, a lower mold 32, and an upper mold 33. The shell mold 31 is generally cylindrical in shape and has an internal space enclosed by the inner circumferential surface 31a of the cylindrical surface. The central axis B of the molding die 30 is an axis that passes through the center of the inner circumferential surface 31a and extends in the vertical direction, corresponding to the optical axis A of the lens 10 formed using the molding die 30.

[0073] The lower mold 32 has an insertion portion 32a that inserts into the interior space of the shell mold 31 from below; and a large-diameter portion 32b disposed below the insertion portion 32a, having a diameter larger than the insertion portion 32a. The insertion portion 32a of the lower mold 32 can be inserted until the large-diameter portion 32b abuts against the lower end face of the shell mold 31. The upper mold 33 is inserted into the interior space of the shell mold 31 from above. The outer peripheral surfaces of the insertion portion 32a of the lower mold 32 and the outer peripheral surfaces of the upper mold 33 can slide vertically relative to the inner peripheral surface 31a of the shell mold 31, and their movement is restricted in the direction perpendicular to the central axis B. That is, when the core is adjusted so that the centers of the lower mold 32 and the upper mold 33 are aligned with the central axis B, the lower mold 32 and the upper mold 33 can move vertically relative to the shell mold 31.

[0074] The lower mold 32 has a pressing surface 34 at the upper end of the insertion portion 32a. The pressing surface 34 has a concave optical surface forming surface 35, an intermediate surface 36 surrounding the optical surface forming surface 35, and a conical surface 37 surrounding the intermediate surface 36. The pressing surface 34 is configured to be concave relative to the upper end surface of the lower mold 32.

[0075] The upper mold 33 has a pressing surface 38 at its lower end. The pressing surface 38 has a concave optical surface forming surface 39, a flat surface 40 surrounding the optical surface forming surface 39, and a conical surface 41 surrounding the flat surface 40.

[0076] When forming the lens 10 using the forming mold 30, a glass preform made of glass, which serves as the base material for the lens 10, is placed on the pressing surface 34 of the lower mold 32. The recessed shape of the optical surface forming surface 35 is used to hold the glass preform in a position on the central axis B. The lower mold 32 is held at a pressing moving end that abuts the large-diameter portion 32b against the lower end face of the shell mold 31. The lower mold 32 is supported from below in a manner that prevents the insertion portion 32a from detaching from the shell mold 31.

[0077] The glass preform is heated to above its glass transition temperature to soften it, and then pressed downwards against the upper mold 33, which has been inserted into the shell mold 31. The glass preform is squeezed and deformed between the pressing surface 38 of the descending upper mold 33 and the pressing surface 34 of the lower mold 32, which restricts its descent.

[0078] When the upper mold 33 is lowered to Figure 3When the pressing moving end is shown, the glass preform takes on a shape corresponding to the mold space between the lower mold 32 and the upper mold 33, and is formed into a lens 10 with the surface shapes of the pressing surfaces 34 and 38 respectively transferred onto it. Then, after cooling to a predetermined temperature, the forming mold 30 is disassembled, so that the formed lens 10 can be removed.

[0079] The first optical surface 12 of the lens 10 is formed by the optical surface forming surface 35 of the lower mold 32, the middle surface 15 of the lens 10 is formed by the middle surface 36 of the lower mold 32, and the position reference surface 16 of the lens 10 is formed by the conical surface 37 of the lower mold 32.

[0080] The optical surface forming surface 35 is a concave surface (non-spherical surface) corresponding to the first optical surface 12 of the convex surface.

[0081] The intermediate surface 36 has: a flat surface 36a, which corresponds to the flat surface 15a of the intermediate surface 15; and a conical surface 36b, which corresponds to the conical surface 15b. The flat surface 36a is a plane perpendicular to the central axis B. The conical surface 36b is a truncated cone shape (the side of a truncated cone) centered on the central axis B, and the diameter of the conical surface 36b increases as it advances towards the top (above) of the insertion portion 32a of the lower mold 32.

[0082] The cone surface 37 is a truncated cone shape (the side of the truncated cone) centered on the central axis B. The diameter of the cone surface 37 increases as the top (above) of the insertion part 32a of the lower mold 32 advances.

[0083] The second optical surface 13 of the lens 10 is formed by the optical surface forming surface 39 of the upper mold 33, the flat surface 17 of the lens 10 is formed by the flat surface 40 of the upper mold 33, and the inner conical surface 18 of the lens 10 is formed by the conical surface 41 of the upper mold 33.

[0084] The optical surface forming surface 39 is a concave surface (non-spherical surface) corresponding to the second optical surface 13 of the convex surface.

[0085] Flat plane 40 is a plane perpendicular to the central axis B.

[0086] Conical surface 41 is a truncated cone shape centered on the central axis B (the side of the truncated cone), and the diameter of conical surface 41 decreases as it moves towards the top (bottom) side of the upper mold 33.

[0087] When manufacturing lens 10 using molding die 30, various errors may occur, such as the capacity error of the glass preform, the volume error of the mold space inside molding die 30, and the deviation of the supply position of the glass preform.

[0088] exist Figure 3At the pressing moving ends of the lower mold 32 and upper mold 33 shown, gaps 42 exist at the periphery of the pressing surfaces 34 and 38. At the location of gap 42, variations in the shape of the glass preform during molding are permissible, and the shape of the lens 10 varies according to the aforementioned errors. The portion of the shape that allows for deviations corresponding to this gap 42 is the volume absorption portion 19 of the edge 14 of the lens 10. Therefore, Figure 1 and Figure 2 The shape of the volume absorption section 19 shown is an example, and the shape of the volume absorption section 19 varies depending on the degree of error. Moreover, by having the volume absorption section 19, other parts of the lens 10 can be formed with high precision.

[0089] The lower mold 32 and the upper mold 33 are constructed using materials such as ceramic or superhard alloy to ensure sufficient durability in the high-temperature environment during lens forming. Figure 4 The process of forming the pressing surface 34 of the lower mold 32 by a manufacturing apparatus for manufacturing lens forming molds is shown. The pressing surface 34 is formed by grinding using a grinding wheel 50 constituting the manufacturing apparatus.

[0090] The grinding wheel 50 is cylindrical and can rotate around its central axis, the rotation axis C. In the manufacturing apparatus, the angle of the rotation axis C can be changed. The grinding wheel 50 uses the corner portion where the end face 50a and the side face 50b meet as the machining point S, making it contact the lower die 32, and performs grinding while rotating around the rotation axis C.

[0091] like Figure 4 and Figure 5 As shown, when the optical surface forming surface 35 of the pressing surface 34 is formed by grinding using the grinding wheel 50, the rotation axis C is typically tilted at 45° relative to the normal K of the optical surface forming surface 35 at the position in contact with the processing point S. When grinding is performed in this manner, it is preferable that the diameter of the grinding wheel 50, i.e., the grinding wheel diameter φg (the diameter of the end face 50a in the direction perpendicular to the rotation axis C), satisfies the following condition (5). R1 ​​is the paraxial radius of curvature of the first optical surface 12 of the lens 10 described above. Since the shape of the optical surface forming surface 35 is transferred to the first optical surface 12, R1 is included in the dimensional conditions of the grinding wheel 50 that forms the optical surface forming surface 35.

[0092] (5)

[0093] By satisfying condition (5), the grinding wheel 50 can process the optical surface forming surface 35 without interfering with the lower mold 32 at locations other than processing point S. Furthermore, the smaller the grinding wheel diameter φg, the less likely interference will occur between the grinding wheel 50 and other parts of the lower mold 32. However, on the other hand, since shape errors in the optical surface forming surface 35 are more likely to occur, it is preferable to use the largest possible grinding wheel diameter φg within the range of condition (5). In this embodiment, a grinding wheel 50 with φg = 1.1R1 is used.

[0094] The pressing surface 34 of the lower mold 32 includes an optical surface forming surface 35, an intermediate surface 36, and a conical surface 37. Particularly stringent precision is required for the optical surface forming surface 35 and the conical surface 37. The optical surface forming surface 35 forms the first optical surface 12, and its surface precision is directly related to the optical performance of the lens 10. The conical surface 37 forms the position reference surface 16, and its surface precision significantly affects the positional accuracy of the lens 10.

[0095] Here, using the same mold 50 to form the optical surface forming surface 35 and the conical surface 37 has several advantages. First, when manufacturing the pressed surface 34, it is not necessary to change the machining tool at each forming location, thus improving production efficiency. Furthermore, since the same mold 50 is used for forming, it is easier to manage the overall precision of the pressed surface 34, including the optical surface forming surface 35 and the conical surface 37.

[0096] On the other hand, when forming each part of the pressing surface 34 using the same grinding wheel 50, it is necessary to consider the possibility of interference between the grinding wheel 50 and the lower die 32 at locations other than the machining point S. In particular, when the pressing surface 34, which is deepest at the center of the central axis B and shallowest at the outer periphery away from the central axis B, forms a conical surface 37 on the outer periphery after forming the optical surface forming surface 35 on the center side, it is required that the grinding wheel 50 not contact the optical surface forming surface 35 during the formation of the conical surface 37.

[0097] Figures 5 to 7 This is an enlarged sectional view (including the section containing the central axis B) of the pressing surface 34 of the lower die 32 and the mold 50. Additionally, in Figures 5 to 7 Although the shape of the pressed surface 34 in its completed state is shown, in reality, because the machining using the mold 50 is performed in stages, each part of the pressed surface 34 is completed sequentially. For example, when machining is performed from the central side of the pressed surface 34 toward the peripheral side, Figure 5 The optical surface forming surface 35 shown is in the processing stage, but the intermediate surface 36 and the conical surface 37 are not completed.

[0098] Since the first optical surface 12, intermediate surface 15, and position reference surface 16 of lens 10 transfer the shape of the pressing surface 34 of lower mold 32, the description of the conditions of lower mold 32 also uses elements (w, d, θ, R1, La, Lb, Ld) common to the conditions of lens 10 described above. Furthermore, the central axis B in the description of lower mold 32 is synonymous with the optical axis A, which reflects the condition of lens 10.

[0099] On the pressing surface 34, the outer edge of the optical surface forming surface 35 is designated as the outer edge Q11 of the optical surface forming surface. Furthermore, the portion of the conical surface 37 that intersects with the intermediate surface 36 (conical surface 36b) is designated as the inner edge Q12 of the conical surface, and the outer edge on the opposite side of the inner edge Q12 is designated as the outer edge Q13 of the conical surface. The outer edge Q11 of the optical surface forming surface corresponds to the outer edge Q1 of the optical surface of the lens 10, the inner edge Q12 of the conical surface corresponds to the inner edge Q2 of the position reference surface of the lens 10, and the outer edge Q13 of the conical surface corresponds to the outer edge Q3 of the position reference surface of the lens 10.

[0100] Let w be the distance perpendicular to the central axis B (optical axis A) from the outer edge Q11 of the optical surface to the inner edge Q12 of the conical surface. Let d be the distance parallel to the central axis B (optical axis A) from the outer edge Q11 of the optical surface to the inner edge Q12 of the conical surface. Let ψ be the angle between the line segment La connecting the outer edge Q11 of the optical surface and the inner edge Q12 of the conical surface and the vertical line Lb perpendicular to the central axis B (optical axis A). Let θ be the angle between the conical surface 37 and the vertical line Lb.

[0101] exist Figures 5 to 7 In the cross-section shown (including the central axis B), the intermediate surface 36 of the lower mold 32 is contained within a triangular region enclosed by line segment La, vertical line Lb, and the extension line Lc of the conical surface 37. The flat surface 36a is the surface along the vertical line Lb, and the conical surface 36b is the surface located between line segment La and the extension line Lc; the intermediate surface 36 satisfies this condition. Furthermore, the intermediate surfaces 15 (flat surface 15a, conical surface 15b) of the lens 10, corresponding to the intermediate surface 36, are also contained within this triangular region.

[0102] Unlike the intermediate surface 36, if the optical surface forming surface 35 and the conical surface 37 are connected via a surface passing through the outside of the aforementioned region, the shape processing between the optical surface forming surface 35 and the conical surface 37 becomes more complex (e.g., creating the need to use processing tools other than the mold 50), which can easily lead to interference between the mold 50 and the lower mold 32.

[0103] Here, the pressing surface 34 of the lower die 32 preferably satisfies the following conditions (6) and (7).

[0104] (6) φ<45°

[0105] (7) φ<θ

[0106] By satisfying conditions (6) and (7) regarding the inclination of line segment La, which is one side of the defined area of ​​the intermediate surface 36, partial interference between the grinding mold 50 and the intermediate surface 36 can be prevented when forming the conical surface 37 using the grinding mold 50. In cases where ψ ≥ 45° outside the range of condition (6) and ψ ≥ θ outside the range of condition (7), the determination of whether the grinding mold 50 interferes with the lower mold 32 (intermediate surface 36) becomes complicated.

[0107] Next, regarding the inclination of cone 37, for the case where 0° < θ < 45° ( Figure 6 ) and the case of 45°≤θ<90° ( Figure 7 These two cases will be explained. In either case, when forming the conical surface 37 by the mold 50, the machining is performed in a state in which the side surface 50b (rotation axis C) of the mold 50 is tilted at 45° relative to the finished shape of the conical surface 37 within the cross section containing the central axis B of the forming mold 30.

[0108] like Figure 6 and Figure 7 As shown, when the conical surface 37 is formed within the range from the inner edge Q12 to the outer edge Q13 of the conical surface, if the machining point S where the grinding wheel 50 contacts the lower die 32 is the inner edge Q12 of the conical surface, the end face 50a of the grinding wheel 50 is located at the lowest point (near the optical surface forming surface 35), creating a situation where interference with the lower die 32 is likely to occur. Therefore, it is sufficient to confirm whether there is interference between the grinding wheel 50 and the lower die 32 at positions other than the machining point S, at least when the machining point S is at the inner edge Q12 of the conical surface.

[0109] [Case where 0° < θ < 45°]

[0110] like Figure 6 As shown, when 0° < θ < 45°, if the rotation axis C (side surface 50b) of the grinding wheel 50 is tilted at 45° relative to the finished shape of the conical surface 37, then with the machining point S located at the inner edge Q12 of the conical surface, the farthest point T on the end face 50a of the grinding wheel 50, which is furthest from the machining point S, is located higher than the machining point S (in the direction away from the pressing surface 34 along the central axis B). That is, the end face 50a of the grinding wheel 50 is tilted away from the pressing surface 34 with the machining point S as the base. Moreover, during the machining of the conical surface 37 by the grinding wheel 50 in the range from the inner edge Q12 to the outer edge Q13 of the conical surface, the machining point is always at the lowest position on the end face 50a, and the grinding wheel 50 will not contact the lower die 32 in any part other than the machining point S. Therefore, when 0° < θ < 45°, it is sufficient as long as at least the above conditions (6) and (7) are met.

[0111] [Case where 45°≤θ<90°]

[0112] like Figure 7 As shown, when 45° ≤ θ < 90°, if the rotation axis C (side surface 50b) of the grinding wheel 50 is tilted at 45° relative to the finished shape of the conical surface 37, then with the machining point S located at the inner edge Q12 of the conical surface, the farthest point T on the end face 50a of the grinding wheel 50, which is furthest from the machining point S, is located lower than the machining point S (in the direction along the central axis B, closer to the pressing surface 34). That is, the end face 50a of the grinding wheel 50 is tilted towards the pressing surface 34 with the machining point S as the base. At this time, the following condition is set so that the farthest point T does not interfere with the lower mold 32 (especially the optical surface forming surface 35).

[0113] When the rotation axis C of the grinding wheel 50 is tilted at 45° relative to the finished shape of the conical surface 37, the angle between the end face 50a of the grinding wheel 50 and the vertical line Lb perpendicular to the central axis B is θ-45°. The distance χ between the machining point S and the farthest point T along the direction (optical axis direction) of the central axis B is χ=φg·sin(θ-45°).

[0114] Here, by satisfying the following condition (8), it is possible to ensure that the farthest point T does not contact the lower mold 32 when the machining point S is located at the inner edge Q12 of the cone surface, thereby avoiding interference between the mold 50 and the lower mold 32.

[0115] (8)d>χ

[0116] If condition (8) is not met, i.e., d≤χ, since the position of the farthest point T in the direction along the central axis B (optical axis direction) is lower than the outer edge Q11 of the optical surface forming surface (closer to the side of the lower mold 32), the mold 50 may interfere with the optical surface forming surface 35 of the lower mold 32.

[0117] Furthermore, when 45°≤θ<90°, and the machining point S is located at the inner edge Q12 of the conical surface, the interference between the grinding wheel 50 and the lower die 32 near the machining point S needs to be considered. Near the machining point S, if there is a gap between the end face 50a of the grinding wheel 50 and the line segment La, then the grinding wheel 50 and the lower die 32 (especially the middle surface 36) will not interfere.

[0118] Here, by satisfying the following condition (9), it is possible to have a gap angle between the end face 50a of the mold 50 and the line segment La near the machining point S, so as to prevent the end face 50a from interfering with the lower mold 32 (especially the middle surface 36).

[0119] (9) θ - 45° < φ

[0120] Summarizing the above conditions, the results are as follows. When 0° < θ < 45°, it is sufficient to satisfy ψ < 45° in condition (6) and ψ < θ in condition (7). Based on condition (6), we can deduce that d < w in condition (1) above. Based on condition (7), we can deduce that d < w · tanθ in condition (2) above.

[0121] Therefore, when 0° < θ < 45°, by satisfying d < w in condition (1) and d < w·tanθ in condition (2), it is possible to form the pressing surface 34 of the lower mold 32, which includes the optical surface forming surface 35 and the conical surface 37, using a common mold 50. Moreover, in the lens 10 that has the shape of the pressing surface 34 of the lower mold 32 transferred, it is also possible to form a shape that satisfies both conditions (1) and (2).

[0122] When 45°≤θ<90°, in addition to ψ<45° in condition (6) and ψ<θ in condition (7), we also add θ-45°<ψ in condition (9). Based on these conditions, we get θ-45°<ψ<45°<θ, and derive w·tan(θ-45°)<d<w<w·tanθ in the above condition (3).

[0123] Furthermore, when less than 45°≤θ<90°, for the grinding diameter φg of grinding wheel 50, according to the root of φg in condition (5), 8 according to the condition R1, φg=1.1R1, from the condition (8) d>χ, the above condition (4) d>1.1R1·sin(θ-45°) is derived.

[0124] Therefore, when 45°≤θ<90°, by satisfying condition (3) w·tan(θ-45°)<d<w<w·tanθ1 and condition (4) d>1.1R1·sin(θ-45°), it is possible to form the pressing surface 34 of the lower mold 32, which includes the optical surface forming surface 35 and the conical surface 37, using a common mold 50. Moreover, in the lens 10 that has transferred the shape of the pressing surface 34 of the lower mold 32, it is also possible to form a shape that satisfies both conditions (3) and (4).

[0125] As described above, in this embodiment, for a lens 10 positioned using a conical position reference surface 16 inclined relative to and orthogonal to the optical axis, and for a molding die 30 (lower die 32) that presses the lens 10, by satisfying the conditions described above, a pressing surface 34 including an optical surface forming surface 35 and a conical surface 37 can be formed using the same mold 50. Therefore, the lower die 32 can be manufactured efficiently, which helps to improve the productivity of the lens 10 formed using the molding die 30.

[0126] Furthermore, the lens of this utility model is not limited to the above-described embodiments and can be modified within the scope of the utility model's intent. For example, although in Figure 1 and Figure 2 In the lens 10 shown, the position reference surface 16 constituting the outer peripheral surface of the flange portion 14b is substantially parallel to the inner conical surface 18 constituting the inner peripheral surface of the flange portion 14b, but is not limited to this structure.

[0127] Figure 8 A modified example of the flange portion 14b of the edge portion 14 of the lens 10 is shown. Figure 8 The flange portion 14b shown has an inner conical surface 20 in the shape of a frustum centered on the optical axis A, which serves as an inner peripheral surface located on the inner side of the optical axis orthogonal direction, more so than the position reference surface 16. Similar to the inner conical surface 18 in the above embodiment, the inner conical surface 20 is a surface whose radius of curvature (the radius of curvature of the circle centered on the optical axis A and passing through the inner conical surface 20) increases as it advances in the optical axis direction toward the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13).

[0128] As a difference from the above embodiment, the inner conical surface 20 is not parallel to the position reference surface 16. The inclination angle θ1 of the position reference surface 16 relative to the surface P perpendicular to the optical axis A and the inclination angle θ2 of the inner conical surface 20 relative to the surface P perpendicular to the optical axis A are in the relationship that θ1 > θ2. That is, the flange portion 14b has a top-thin shape where the distance between the position reference surface 16 and the inner conical surface 20, i.e., the thickness, decreases as it moves from the inner edge side connected to the base portion 14a towards a certain outer edge (top) side of the volume absorption portion 19. By constructing the flange portion 14b in this way, when demolding the lens 10 after pressing it with the molding die 30, the lens 10 can be prevented from adhering to the upper die 33, thereby improving the demolding performance.

[0129] Figure 9 Another variation of the flange portion 14b of the edge portion 14 of the lens 10 is shown. Figure 9 The flange portion 14b shown has an inner curved surface 21, which forms an inner circumferential surface located inside the optical axis orthogonal direction of the position reference plane 16. Similar to the inner conical surface 18 and inner conical surface 20 described above, the inner curved surface 21 is a surface whose radius of curvature (the radius of curvature of the circle centered on the optical axis A and passing through the inner curved surface 21) increases as it advances in the optical axis direction toward the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13).

[0130] like Figure 9 As shown, the inner curved surface 21 also has a concave shape within the cross section containing the optical axis A. Furthermore, the inner curved surface 21 does not have any steps or bends between it and the flat surface 17, and the inner curved surface 21 is smoothly connected to the flat surface 17.

[0131] Unlike Figure 9 The inner curved surface 21 shown is... Figure 1 The inner conical surface 18 of the flange portion 14b shown, and Figure 8 The inner conical surfaces 20 of the flange portion 14b shown are all curved surfaces (side surfaces of the frustum) in the shape of a truncated cone centered on the optical axis A, and are straight in shape within the cross section containing the optical axis A.

[0132] Within the cross-section containing the optical axis A, the inner curved surface 21 can be a circular arc shape with a fixed radius of curvature, or a non-circular curved shape with a variable radius of curvature. Within the cross-section containing the optical axis A, in the case of a circular arc shape with a fixed radius of curvature, the inner curved surface 21 is a concave annular surface.

[0133] In the structure where the flange portion 14b of the edge portion 14 has an inner curved surface 21, the inner curved surface 21 and the flat surface 17 are smoothly connected without any steps or bends in between. Therefore, the load is less likely to be concentrated at the junction of the flat surface 17 and the inner curved surface 21, i.e., the junction of the base portion 14a and the flange portion 14b, which helps to ensure the strength of the lens 10. Furthermore, when manufacturing the lens 10 by pressing and processing the glass preform, it is easier for the glass to flow smoothly from the base portion 14a to the flange portion 14b, thereby improving the forming accuracy of the lens 10.

[0134] Furthermore, since there are no steps or bends between the area for forming the flat surface 17 and the area for forming the inner curved surface 21 on the pressing surface of the forming mold (upper mold), when manufacturing the pressing surface of the forming mold (upper mold), machining tools such as grinding wheels can move with a smooth movement trajectory, enabling high-precision and efficient manufacturing.

[0135] Furthermore, when the inner curved surface 21 is an arc shape with a fixed radius of curvature within a cross section containing the optical axis A, the movement trajectory and direction of the machining tool become simpler when forming the inner curved surface 21 in the pressing surface of the molding die (upper die), thereby improving the manufacturing efficiency of the molding die.

[0136] Figure 10 Another variation of the flange portion 14b of the edge portion 14 of the lens 10 is shown. Figure 10The flange portion 14b shown has an inner curved surface 22, which forms an inner circumferential surface located inside the optical axis orthogonal direction, more so than the position reference plane 16. The inner curved surface 22 differs from the aforementioned inner conical surfaces 18, 20, and 21; it is approximately parallel to the optical axis A and is a cylindrical surface centered on the optical axis A. That is, in the inner curved surface 22, the radius of curvature (the radius of curvature of the circle centered on the optical axis A and passing through the inner curved surface 22) does not change as it moves along the optical axis towards the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13); the radius of curvature remains the same at any position along the optical axis.

[0137] The inner curved surface 22 of this shape can be used as a position reference in the orthogonal direction of the optical axis. For example, in an optical system including lens 10, when optical elements other than lens 10 (other lenses, spacers that determine the position of the lens, etc.) are arranged, the other optical elements can be made to abut against the inner curved surface 22 of lens 10 to determine their position in the orthogonal direction of the optical axis. Since lens 10 is positioned relative to a holding member (not shown) via position reference surface 16, the other optical elements are positioned via lens 10.

[0138] As shown in the above embodiments and variations, the structure of the inner peripheral surface of the flange portion 14b, located further inside the optical axis orthogonal direction than the position reference plane 16, can be broadly categorized into: surfaces whose radius of curvature increases as they advance in the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13) along the optical axis (inner conical surface 18, inner conical surface 20, inner curved surface 21); and surfaces whose radius of curvature does not change as they advance in the second direction A2 (from the side of the first optical surface 12 to the side of the second optical surface 13) along the optical axis (inner curved surface 22). In this way, various structures can be selected for the inner peripheral surface of the flange portion 14b, and the most suitable shape can be used according to the preferred conditions. Furthermore, Figures 8 to 10 The lens 10 of each of the shown variations satisfies the requirements of the lens 10 of the above-described embodiment. Figure 1 and Figure 2 (The already determined conditions)

[0139] Although the first optical surface 12 and the second optical surface 13 of the lens 10 in the above embodiments are both aspherical lenses, the lens of this invention is not limited to aspherical lenses and can also be applied to spherical lenses. Furthermore, the second optical surface 13 can be concave instead of convex.

[0140] The embodiments of this utility model are not limited to the above-described embodiments and their variations. Various changes, substitutions, and modifications can be made without departing from the spirit and essence of the technical concept of this utility model. Furthermore, if the technical concept of this utility model can be realized by other methods based on technological advancements or derived technologies, those methods can also be used. Therefore, the scope of the patent claims covers all embodiments that still fall within the scope of the technical concept of this utility model.

[0141] Explanation of reference numerals in the attached figures

[0142] 10: Lens;

[0143] 11: Optical Functional Unit;

[0144] 12: First optical surface;

[0145] 13: Second optical surface;

[0146] 14: Edge section;

[0147] 14a: Base;

[0148] 14b: Flange portion;

[0149] 15: Middle surface;

[0150] 15a: Flat surface;

[0151] 15b: Conical surface;

[0152] 16: Position reference plane;

[0153] 17: Flat surface;

[0154] 18: Inner conical surface;

[0155] 19: Volume absorption section;

[0156] 20: Inner conical surface;

[0157] 30: Molding mold (lens molding mold);

[0158] 31: Shell mold;

[0159] 32: Lower mold (mold component);

[0160] 33: Upper mold;

[0161] 34: Pressing surface;

[0162] 35: Optical surface forming surface;

[0163] 36: Middle surface;

[0164] 36a: Flat surface;

[0165] 36b: Conical surface;

[0166] 37: Conical surface;

[0167] 38: Pressed surface;

[0168] 39: Optical surface forming surface;

[0169] 40: Flat surface;

[0170] 41: Conical surface;

[0171] 42: Gap;

[0172] 50: Abrasive mold (a device for manufacturing lens forming dies);

[0173] 50a: The end face of the abrasive;

[0174] A: Optical axis;

[0175] B: The central axis of the molding die;

[0176] C: The rotating axis of the mold;

[0177] Q1: Outer edge of the optical surface;

[0178] Q2: Inner edge of the location reference plane;

[0179] Q3: Outer edge of the location reference plane;

[0180] Q11: Outer edge of the optical surface forming surface;

[0181] Q12: Inner edge of the cone surface;

[0182] Q13: Outer edge of the cone surface;

[0183] S: Processing point;

[0184] T: farthest point;

[0185] φg: Grinding tool diameter.

Claims

1. A lens, which is a pressed-molded product, characterized in that, have: An optical functional unit has a first optical surface, which is a convex surface facing one side toward the optical axis, and a second optical surface facing the other side toward the optical axis. The edge portion, located on the outer side of the optical functional part away from the optical axis, has a position reference plane located on the outer side of the first optical surface, the position reference plane being inclined relative to both the optical axis direction and the direction orthogonal to the optical axis; and The volume absorption portion is disposed on the edge portion, located on the inner side of the optical axis orthogonal direction, which is further from the outer edge of the position reference plane, to allow for shape errors associated with pressing and molding.

2. The lens according to claim 1, characterized in that, The edge portion has a base portion that surrounds the optical functional portion, and a flange portion located outside the base portion. The base is formed in a ring shape extending generally in a direction orthogonal to the optical axis from the optical functional part. The flange portion protrudes from the first optical surface side to the second optical surface side in the optical axis direction relative to the base portion, and is a conical annular portion inclined relative to the optical axis direction.

3. The lens according to claim 2, characterized in that, The volume absorption portion is disposed at the end of the flange portion and is not on the extension line of the position reference plane.

4. The lens according to claim 1, characterized in that, The edge has an intermediate surface located outside the first optical surface and a position reference surface located outside the intermediate surface.

5. The lens according to claim 1, characterized in that, The edge has a flat surface located outside the second optical surface and an inner conical surface located outside the flat surface.

6. The lens according to claim 1, characterized in that, The position reference surface is shaped like a frustum of a cone, and its radius of curvature increases as it moves along the optical axis from the first optical surface side to the second optical surface side.

7. The lens according to claim 1, characterized in that, The volume absorption portion is located in the orthogonal direction of the optical axis, which is further inward than the outer edge of the position reference plane, and in the optical axis direction, it is located on the back side of the position reference plane.

8. The lens according to claim 1, characterized in that, The angle θ of the position reference plane relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction perpendicular to the optical axis, and the distance d from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction parallel to the optical axis, satisfy the following conditions (1) and (2) when 0° < θ < 45°: (1)d<w (2)d<w·tanθ.

9. The lens according to claim 1, characterized in that, The angle θ of the position reference plane relative to the plane perpendicular to the optical axis, the distance w from the outer edge of the first optical surface to the inner edge of the position reference plane in the direction perpendicular to the optical axis, the distance d from the outer edge of the first optical surface to the inner edge of the position reference plane parallel to the optical axis, and the paraxial radius of curvature R1 of the first optical surface, when 45°≤θ<90°, satisfy the following conditions (3) and (4): (3)w·tan(θ-45°)<d<w<w·tanθ (4)d>1.1R1·sin(θ-45°).

10. The lens according to claim 1, characterized in that, The position reference plane is located on the outer periphery of the edge. The edge portion, located on the inner side of the optical axis more orthogonal to the position reference plane, has a curved surface whose radius of curvature increases as it moves along the optical axis from the first optical surface side to the second optical surface side, or has the same radius of curvature. The volume absorption portion is provided at the end of the flange portion, which uses the position reference surface as the outer peripheral surface and the curved surface as the inner peripheral surface.

11. The lens according to claim 10, characterized in that, The curved surface is the inner cone surface of a frustum shape whose radius of curvature increases as it moves from the first optical surface side to the second optical surface side in the optical axis direction.

12. The lens according to claim 11, characterized in that, The position reference plane has a larger tilt angle relative to the plane perpendicular to the optical axis compared to the inner conical surface.

13. The lens according to claim 10, characterized in that, The surface is a surface whose radius of curvature increases as it moves along the optical axis from the first optical surface side to the second optical surface side, and which has a concave shape within a cross section containing the optical axis.

14. The lens according to claim 1, characterized in that, There is an intermediate surface between the first optical surface and the position reference surface. Within a cross section containing the optical axis, the intermediate surface lies within the region bounded by the line segment connecting the outer edge of the first optical surface and the inner edge of the position reference surface, the straight line extending from the outer edge of the first optical surface in the orthogonal direction of the optical axis, and the straight line extending the position reference surface.

15. A lens forming mold, which forms the lens according to claim 1, characterized in that, It has: a mold component having an optical surface forming surface having a shape corresponding to the first optical surface, and a position reference surface forming surface having a shape corresponding to the position reference surface.

16. An apparatus for manufacturing a lens forming mold, comprising manufacturing the lens forming mold of claim 15, characterized in that, It comprises: a cylindrical abrasive, which forms the optical surface forming surface and the position reference surface forming surface of the mold component by rotating about a central axis. The paraxial radius of curvature R1 of the first optical surface of the lens and the diameter φg of the end face of the grinding tool satisfy the following condition (5):

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